I have a 1.5 year old Armstrong Furnace that seems to break and fix itself...A couple weeks ago we woke up to a cold house and the furnace wouldn't stay on for more than a few seconds (inducer would start, igniter heat up, gas fire but then shut off after at most a minute or two). I turned the furnace off and back on and it started up no problems and the house heated back up. A week ago, the same thing happened except this time off/on didn't fix it. Taking the advice from another thread in this forum I checked the outside vents, changed the filter, cleaned the flame sensor, changed batteries in my thermostat, but nothing helped. The error it gave was "Pressure switch open with inducer on." Had a tech come and he checked everything and found a bunch of dirt in the drain coming off the furnace. After he cleaned that out it started up no problem. He had thought it might be a faulty pressure switch but it was opening/closing when he used suction on the little tube attached to it. Yesterday I woke up to a cold house again, checked the drain and everything else, no problems. A couple hours later, it started up and stayed on (I had taken a break from looking at it, I did nothing between trying it and it not working and then it starting up.) Worked fine all day yesterday and then this morning the house was cold again. Turned it off/on and it started up and has kept the house warm so far. My thermostat is set to just hold a temperature, no schedule. There is a humidifier attached to the furnace that's been there for about a year. There's also an HRV. If there's any other info you need let me know. I feel a little strange calling a tech to come look at a furnace that is working fine at the moment, but it seems pretty clear something is wrong. Any help would be appreciated! Steve

We are having an issue with our Rheem Classic Oil Furnace (model R0BD-1120BGA). We had the furnace repair man out 2x to try and resolve this and after about $750 in replaced parts it is doing the same exact thing still. I'm pretty handy, but need help troubleshooting this. Here's what is happening. The furnace will fire up and run fine. it could run fine for several hours or a couple of days, but at some point I notice the house is cooler than it should be and I go down into the basement to see the red light illuminated on ththe Honeywell primary controller. I turn off the service power switch press the reset switch and everything fires back up immediately. I don't see a puff of smoke in the exhaust stack so I don't think the furnace has excess oil when I restart it. Things I have done to troubleshoot so far: *checked the light/fire sensor on the ignition coil to see if it has junk on it or is cracked. No issues there. *checked that there is continuity on the F-F wires going from the Honeywell primary to the light sensor. No issue there. *pulled out the over temp sensor in the exhaust stack and it looks pristine. No obvious corrosion. *the nozzle was replace by the furnace repair man during the last visit. Still had the issue after the visit. *checked the electrodes for corrosion between the spring connection of the transformer and the electrode. No obvious corrosion or discoloration. *repairman replaced the combustion blower motor. It was making a little more noise than normal on startup and he thought it may be causing the furnace to kick off after a while. No change after spending good money to replace it. Although the furnace is running slightly quieter. Could it be the Honeywell primary?? I'd rather do some troubleshooting to figure it out for sure before spending any more money if possible. Furnace info: Rheem Classic Model: R0BD-1120BGA Beckett Oil Burner Model "AFG" (sticker is a little messed up so the F may be an R Honeywell Primary Model R8184M 1051 Beckett Combustion Motor Model Y5L271C81 Danfoss Oil Pump Model BFPH 071N1151 Any advice you could offer would be appreciated!